#define _CRT_SECURE_NO_WARNINGS 1

#include <stdio.h>

int max3(int a, int b, int c)
{
    if (a > b && a > c)
        return a;
    else if (b > a && b > c)
        return b;
    else
        return c;
}

int main() {
    int a = 0;
    int b = 0;
    int c = 0;
    scanf("%d %d %d", &a, &b, &c);
    int k = max3(a, b, c);
    float m = 1.0*max3(a + b, b, c) / (max3(a, b + c, c) + max3(a, b, b + c));
    printf("%.2f\n", m);
    return 0;
}